Rotary displacement device



March 6, 1951 C, BANCROFT 2,544,481

ROTARY DISPLACEMENT DEVICE Filed April 24, 194'? 4 Sheets-Sheet l iINVENToR.

March 6, 1951 c. BANcRoF-r A 2,544,481

ROTARY DISPLACEMENT DEVICE Filed April 24, 1947 4 Sheets-Sheet 2JNVENToR. @HAM-fs BAA/Worf TTO/Q/VEVS March 6, 1951 c. BANcRoF'r2,544,481

ROTARY DISPLACEMENT DEVICE Filed April 24, 194'? 4 Sheets-Shee'cl 3ff/f@ JNVENToR.

Patented Mar. 6, 1951 UNITED STATES 'PATENT OFFICE ROTARY DISPLACEMENTDEVICE Charles Bancroft, New Canaan, Conn.

Application April 24, 1947, Serial No. 743,517

This invention relates to rotary displacement devices and moreespecially to rotary displacement devices of the alternatelyaccelerating piston type.

An object of this invention is a rotary displacement device of thealternating accelerating piston type of such structure that thedirection of flow oi' compressible fluid through the device may beeasily and quickly reversed or that the most eiiicient valve setting forvarying working pressures may be automatically obtained.

A further object of the invention is an alternately accelerating pistonrotary displacement device Which is of improved operationalcharacteristics and of simplied construction.

Other objects, novel features and advantages of this invention willbecome apparent from the following specication and accompanyingdrawings, wherein:

Fig. 1 is a vertical section through a device embodying the invention;

Fig. 2 is a section on the line 2 2 of Fig. l;

Fig. 3 is a section on the line 3-3of Fig. 1;

Fig. 4 is a section on the line 4 4 of Fig. 1 with the pistons in oneposition;

Fig. 5 is a section on the line 5-5 of Fig. 1 with the pistons slightlychanged from the position of Fig. 4;

Fig. 5a is afragmentary view similar to Fig. 5 with certain parts in adifferent relation;

Fig. 6 is a fragmentary view-partially in section of a form of controlmechanism, .and

Figs. 7 and 8 are exploded views of units of the device.

The enclosing casing for the moving parts consists of a center annularmultiple-part section IIJ and two end sections I I and I2 suitablybolted to the center section. The section I0 is'made up of three annularmembers I3, I4 and l5, of which the member I4 is rotatably mounted onthe inner edges of the end sections II and I2 and is l formed withshoulders against which the members I3 and I5 abut with the member I4enclosed by the members I3 and. I5 which are suitably interconnected.Each of the two end sections II and I2 supports an anti-friction bearingI6 in which is journalled one end of a crank shaft Il made up of thevparts I8, I9, and 2l. The part I9 is formed with a crank pin 22 whichprojects into and is keyed to the part I8 while the part 2I is formedwith a crank pin 23 which projects into and isv keyed to the part 20.The part I9 is separable from the part I8 and the part 2l is separablefrom the part 2D to facilitate assembly but when assembled, the partsI8. and I3,

7 Claims. (Cl. 10S-129) as well as the parts 2U andA 2| are in effectunitary. The inner end of the part I9 is reduced as shown at Ia and isreceived in a correspondingly shaped socket 2id formed in the inner endof the part 2| and the parts IS and 2| are keyed together. The innerends of the parts I9 and 2| cooperate to form a cylindrical pin I lacoaxial of the crank shaft Il.

A disk 24 is journalled on each of the crank pins 22 and 23 and isformed with a hub 25 rotatably tting an aperture in a block 26 slidablein a groove in a non-rotatable plate 21 mounted in the end casing II orI2. Each disk 24 has three radial grooves 28 in each of which isslidably mounted a block 29. Each of two spaced disks 30 has a hub 3ljournalled on the crankshaft pin I'Ia and has a stud 32 tting into oneblock 29. Each disk 30 also has an arcuate slot 33 (see Fig. '7) ofapproximately 300 and an annular shoulder 34. Each of two disks 35 isjournalled on the shoulder 34 of one disk 30 and has an arcuateextension 36 projecting into the slot 33 of a disk 30 which extensioncarries a stud 37 tting into a second block 29. In one face of each disk35 there is provided a circular recess 33 in. which is journalled athird disk 39 which has an arcuate extension 40 also projecting into thearcuate slot 33 of a disk 30 through the central aperture 35a of thedisk 35. The extension 40 carries a stud 4I which fits into a thirdblock 23. The three disks 30, 35 and 39 are capable of limited relativerotary movement.

A disk 42 journalled on the hub 3| of each disk 3E! carries twodiametrically opposed pistons 43. Each of the two disks 44 is formedWith an annular shoulder 45 which is journalled in a recess 4B in a disk35 and is formed With a circular recess 4l in which is received a disk42, the threaded flange 48 of which surrounds the hub 3l and is screwedinto the thread 49 of the disk 39. A sleeve 5I] receives the hubs 3l andis xed to the hubs for rotation therewith. The sleeve is formed with apair of diametrically opposed pistons 5I. The piston 43 of each plate 42extends between the pistons 5I of the sleeve 50 into contact with theopposite disk 42 and the opposite disk 44 to which the pistons 43 and adisk 35 are suitably attached. Thus, one piston set 43 connects with oneof the disks'39 on one side oi the assembly and with the disk 44 andhence the disk 35 on the opposite side, and the other piston set 43connects with the disk 44 and hence the disk 35 on said one side andwith the disk 39 on said opposite side. 'I'he disks 42 and 44 togetherwith the sleeve 50 and 3 member I4 form a ring cylinder in which arelocated the pistons 43 and 5 I.

Rotation of the crank shaft Il produces oppositely directed rotation ofthe three pairs of pistons with the piston assembly making one completerotation relative to the casing for each complete rotation of thecrankshaft. During each complete rotation of the piston assembly, thediierent pairs of pistons rotate at varying relative speeds so that theadjacent pistons move relative to each other as they rotate about thecrankshaft axis to form between adjacent pistons chambers of varyingVolume.

The member I3 cooperates with the member I4A to form an annular chamber54 having a port 55. The member I4 is provided with a lug 52 and a slot53 is formed in the periphery of theport 55. The member I5 cooperateswith the member I4 to form an annular chamber 56 having a port 5l. Themembers I3 and I5 are rigidly connected to the end sections II and I2and to each other while the member I4 is supported by said other twomembers for limited rotation about the crankshaft axis. The member I4supports two diametrically related tubular sleeves 58 each of which isreceived in a recess 59 in the member I3,r the recess being of somewhatgreater extent or lengths than the sleeves 58. A port 66 providescommunication between the interior of each sleeve and the chamber 56. Apair of ports 6I and 62 lead from each sleeve 58 through the member I4into the ring cylinder. A plunger 63 having heads 64 and 65 is slidablymounted in each housing 58 and the arrangement is such that in oneposition of the plunger the port 6I is connected to the annular chamber54 with the port 62 con.-

nected to the annular chamber 56 and in another position of the plungerthe port 6I is connected to the annular chamber 56 with the port 62connected to the annular chamber 54. The position of the plunger ischanged by rotating the member I4 from the position shown in Fig. 4 inwhich one end of the sleeve 58 engages one end wall of the recess 59, toa position in which the opposite end of the sleeve 58 engages theopposite end of the recess 59, thereby sliding the plunger 63 into aposition opposite to that shown in Fig. 4. Such rotation of the member5I is accomplished by means of a link 66 pivotally connected at one endto the lug 52 and pivotally connected at approximately its midpoint toan arm 67 carried by a shaft 68 journalled in the member I3 and providedwith an operating handle 66 exterior of the casing. Upon 90 rotation ofthe shaft 68 from its Fig. 5 position by the handle 69, the member I4 ismoved clockwise half-way from its Fig. 4 position to its other positionand the free end of the link 66 moves up into the slot 53 which slotacts as a fulcrum for the free end of the link 66 upon additional 90rotation of the shaft 68 to continue clockwise movement of the member I4to its other position as the shaft 68 is rotated beyond its position inwhich the arm 61 is vertical.

In the member I4 are provided two diametrically opposed arcuate slots'I6 offset axially from the ports 6I and 62. The length of each slot isless than the distance between the ports 6I and 62 and each slot is soarranged that its ends are equally spaced circumferentially from the twoports. These slots provide ports between the annular chamber 54 and thering cylinder.

Assume that the device is being operated as a motor with the member I4in the position shown `in Figs. 4 and 5 with the port 55 open toatmosphere and the port 51 connected to a supply of compressed air. Flowof air through the device rotates the piston at varying speeds to causevariation in the spacing between adjacent faces of successive pistons,thereby forming varying size chambers for expanding the compressed airand scavenging the expanded air. As the pistons rotate clockwise fromtheir Fig. 5 position to their Fig. 4 position and beyond, compressedair admitted throughy the annular chamber 56 and the port 62 forces 4theleading vpiston 5I away from the trailing piston 43 until the trailingpiston 43 closes the port 62. Further clockwise rotation of the pistons..causes the trailing piston 43 to approach the leading piston 5I toscavenge the air from between the pistons through the ports I0 and 6Iinto the annular chamber 54 until the trailing piston 43 covers theports 6I and 'I0 and the same cycle is repeated by each pair of pistons.Rotation of the pistons as above described effects counterclockwiserotation of the crankshaft as previously described. The overlappingarrangement of the disks 42 and 44 in conjunction with the arrangementof the disks 35 and 39 effectively prevents the loss of pressure fromthe ring cylinder through the circular walls thereof.

Reversal of the position ofthe member I4 as above described results inreverse rotationA of the pistons aswell as reverse rotation of thecrankshaft. Upon movement of the membery I4 to engage the opposite endsof the sleeves 58 with theopposite ends of the recessesA 59, the plunger63 is moved into position to connect the port 6I to the port and toYconnect theport 62 through the sleeve 58'to the chamber 54, whereupon owof compressed air through the device effects counterclockwise rotationof the pistons and clockwise rotation of the crankshaft.

As shown in Fig. 6, additional means may be provided for varying theangularV position of the member I4 responsive to pressure changes in thechamber 56 so that compressed fluids trapped between the approachingpiston'maybe admitted to or discharged from the chamber 56 in a mannerto give the highest eiciency of operation of the device for any givenoperating pressure. Thus, for a given inputy pressure, if thedisplacement of the rotary piston is too large or small during the timethe pressure is.introducedfor-expansion to drive the advancing pistonahead; the potential power output ofthe devicemayfbereduced. With theoptimumvdisplacemnt, the fullpower potential is realized. An arm; 1I isixed4 to the shaft 68 and is biased by a spring 12 tending to move themember I4out of its Fig; 4 position. An air cylinder 73 contains apiston-.having an extension 14 connected to the free end of the arm 'IIto swing the arm against the action of the spring 12. A pipe 'I5 leadsfrom the chamber 56 to the cylinder 13' to applyjto the piston thepressure existing in the chamber 56 in opposition to the spring 12.Considering Figs. 4 and 5in conjunction with Fig. 6, an increase in thepressure in the chamber 56 above a setvalue causes movement of thev arm'II ina' direction to eifect counterclockwise movementof the member I4thereby resulting in quicker'closing off of port 62 by the trailingpiston 43 and-thus reducing the volume of the chamber formed between theleading and trailing piston at the time of closing of the port.

The devicemay alsobe used as a pump by suitably connecting the ports 55and 5l one to atmosphere and the other to a compressed air storage tankand 'positively driving-the crankshaft. When the device is used as apump', reversal of the appended claims.

I claim:

l. A device of the character described comprising a ring cylinderincluding two spaced circular wall members and an annulus enclosing saidwall members, a crank shaft having a pin coaxial therewith and extendingbetween said wall members, a casing rotatably supporting said annulusand said crank shaft and formed with a pair of annular chambersrespectively having an inlet and an outlet, two or more pairs of pistonmembers rotatably supported in said cylinder, means interconnecting saidcrank shaft and piston members for effecting rotation of said pistonmembers at varying speeds upon rotation of said crank shaft, two sleevesxed to said annulus in diametrically opposed relation, each sleevehaving two spaced ports communicating with said ring cylinder and athird port intermediate said two ports communicating with one of saidannular chambers, an elongated slot in said annulus intermediate theports of each sleeve and of less extent than the spacing between saidports and communicating with the other of said chambers, means movablein each sleeve between two alternate positions to place alternately oneor the other of said two sleeve ports in communication with said thirdintermediate sleeve port, and means eiective upon rotation of saidannulus in said casing to move said movable means in said sleeves fromone to the other of its two alternate positions.

2. A device of the character described comprising a ring cylinderincluding two spaced circular wall members and an annulus enclosing saidwall members, a crank shaft having a pin coaxial therewith and extendingbetween said `wall members, a casing rotatably supporting said annulusand said crank shaft and formed with a pair of annular chambersrespectively having an inlet and an outlet, two or more pairs of pistonmemat varying speeds upon rotation of said crank shaft, two sleeves xedto said annulus in diametrically opposed relation, each sleeve havingtwo spaced ports communicating with said ring cylinder and a third portintermediate said two ports communicating with one of said annularchambers, an elongated slot in said annulus intermediate the ports ofeach sleeve and of less extent than the spacing between said ports andcommunicating with the other of said chambers, a plunger movable in eachsleeve between two alternate positions and provided with two pistonsadapted in alternate plunger positions to place alternately one or theother of the two sleeve ports in communication with the thirdintermediate sleeve port, a recess in said casing receiving each sleeveand being of greater length than the sleeve, said plunger being ofgreater length than the sleeve for engagement Iwith the ends of saidrecess to locate said plunger in either of its two alternate positionsupon rotation of said annulus,

and means for effecting rotation of said annulus.

3. A device of the character described comprising a ring cylinderincluding two spaced circular wall members and an annulus enclosing saidwall members, a crank shaft having a pin coaxial therewith and extendingbetween said wall members, a casing rotatably supporting said annulusand said crank shaft and formed with a pair of annular chambersrespectively having an inlet and an outlet, two or more pairs of pistonmembers rotatably supported in said cylinder, means interconnecting saidcrank shaft and piston members for effecting rotation of said pistonmembers at varying speeds upon rotation of said crank shaft, two sleevesfixed to said annulus in diametrically opposed relation, each sleevehaving two spaced ports communicating with said ring kcylinder and athird port intermediate said two ports communicating with one of saidannular chambers, an elongated slot in said annulus intermediate theports of each sleeve and of less extent than the spacing between saidports and communicating with the other of said chambers, a plungermovable in each sleeve between two alternate positions and provided withtwo pistons adapted in alternate plunger positions to place alternatelyone or the other of the two sleeve ports in communication with the thirdintermediate sleeve port, a recess in said casing receiving each sleeveand being of greater length than the sleeve, said plunger being ofgreater length than the sleeve for engagement with the ends of saidrecess to locate said plunger in either of its two alternate positionsupon rotation of said annulus, a control shaft rotatably supported bysaid casing, an arm carried by said control shaft within said iirstannular chamber, a link interconnecting said annulus and the free end ofsaid arm, and a handle exterior of said casing for rotating said controlshaft. l

4. A ,device of the character described comprising a ring cylinderincluding two spaced circular wall members and an annulus enclosing saidwall members, a crank shaft having a pin coaxial therewith and extendingbetween said wall members, a casing rotatably supporting said annulusand said crank shaft and formed with a pair of annular chambersrespectively having an inlet and an outlet, two or more pairs of pistonmembers rotatably supported in said cylinder, means interconnecting saidcrank shaft and piston members for effecting rotation of said pistonmembers at varying speeds upon constant speed rotation of said crankshaft, two sleeves fixed to said annulus in diametrically opposedrelation, each sleeve having two spaced ports communicating with saidring cylinder and a third port intermediate said two ports communicatingwith one of said annular chambers, an elongated slot in said annulusintermediate the ports of each sleeve and of less extent than thespacing between said ports and communicating with the other of saidchambers, a plunger movable in each sleeve between two alternatepositions and provided with two pistons adapted in alternate plungerpositions to place alternately one or the other of the two sleeve portsin communication with the third sleeve port, and means effective uponrotation of said annulus in said casing to move said plunger from one tothe other of its two positions.

5. A device of the character described comprising a casing, a crankshaft journalled in said casing and having a pin coaxial with saidshaft, a pair of disks rotatably mounted on said pin, a collar rotatablymounted on said pin, a pair of pistons supported by each .disk incontact with the remaining disk, a third pair of pistons supported bysaid collar between said disks, a second pair of disks each individuallysupported by one of said first pair of disks and connected to thepistons supported by the other of said rst pair of disks, a third pairof .disks rotatably supported by said casing and having inner sectionsoverlapping the outer sections of said first pair of disks, an. annulusenclosing said second pair of disks, and means interconnecting saidfirst pair of disks, saidy second pair ofv disks and said collar to saidcrank shaftfor effectingV rotation of said pistons at varying' speeds`upon rotation of said crank shaft.

6. A device of the character described comprising a casing, a crankshaft journalled in said casing and having a pin coaxial with saidshaft, a pair of disks rotatably mounted on said pin, a

collar rotatably mounted on said pin, a Vpair of pistons supported byeach disk in contact with the remaining disk, a third pair of pistonssupported by said collar between said disks, a second pair of disks eachindividually supported by one of said rst pair of disks and connected tothe pistons supported by the other of said first pair of disks, a thirdpair of disks rotatably supported by said casing and having circularrecesses receiving the peripheries of said first pair of disks, anannulus enclosing said second pair of disks, and means interconnectingsaid rst pair of disks, said second pair of disks and said collar tosaid crank shaft for effecting rotation of said pistons at varyingspeeds upon rotation of said crankshaft.

7. A device of the character described comprising a casing, a crankshaft journalled in said casing and having a pin coaxial with saidshaft, a pair of disks rotatably mounted on said pin, a collar rotatablymounted on said pin, a pair of pistons supported by each disk in contactwith the remaining disk, a third pail` of pistons supported by saidcollar between said disks, a second pair of disks each individuallysupported by one of said first pair of disks and connected to thepistons supported by the other of said first pair of disks, a third pairof disks rotatably supported by said casing and having inner sectionsoverlapping the outer sections of said first pair of disks, an annulusenclosing said second pair of disks rotatably supported by said casing,a pair of annular chambers formed in said casing, said chambersrespectively having an inlet and an outlet, two sleeves fixed to saidannulus in diametrically opposed relation, each sleeve having two spacedports communicating with said ring cylinder and a third portintermediate said two ports communicating with one of said annularchambers, an elongated slot in said annulus intermediate the ports ofeach sleeve and of less extent than the spacing between said ports andcommunicating with the other of said chambers, means movable in eachsleeve between two alternate positions to place alternately one orv theother of the two ports of each sleeve in communication with the thirdport of said sleeve, means effective upon rotation of said annulus insaid casing to move said last-named means from one to the other of itstwo alternate positions, and means interconnecting said rst pair ofdisks, said second pair of disks and said collar to said crank shaft foreffecting rotation of said pistons at varying speeds upon rotation ofsaid crank shaft.

CHARLES BANCROFT.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,838,252 Coppage Dec. 29, 19311,843,155 Gronemeyer Feb. 2, 1932 1,921,747 Greve Aug. 8, 1933 1,997,233Rodaway Apr. 9, 1935 2,096,074 Stevens Oct. 19, 1937 2,132,596 BancroftOct. 11, 1938 2,222,706 English Nov. 26, 1940 2,243,653 Rodaway Nov. 27,1941 2,270,493 Bancroft Jan. 20, 1942 FOREIGN PATENTS Number CountryDate 444,706 Great Britain Mar. 25, 1936

